To provide a method and a device for efficiently filling powder applicable to spherical toner powder of high circularity, in particular, spherical toner powder pelletized by a polymerization method, preventing detachment or embedding of additive, and preventing spherical toner powder from remaining in a powder storage tank after a filling step.

A gas outlet opening formed in a tip of a filling nozzle 17 is inserted in a powder filling container 18, and spherical powder formed of at least polymer with the circularity being ≥ 0.95 and below 0.99 is stored in a powder storage tank so that the volumetric ratio of powder to air reaches 0.8-5.0 in terms of powder. Then, air is introduced from an air inlet opening into the powder storage tank to fluidize powder. The fluidized powder is discharged together with air through a feed pipe from a tip part of the filling nozzle into the powder storage container to fill powder into the powder storage container.